The National Cancer Institute has set a goal of having 80 percent of women age 50 and above receiving regular mammography by the year 2000. The only time this goal has been approached in large populations is when women received mailed invitations to screening. The overall objective of this research is to evaluate strategies for maximizing participation in breast cancer screening using written invitations. The specific aims of the proposed research are to test the effect on breast cancer screening participation, in women age 50 and above, of: 1) involving the primary care team as the source of the invitations, and 2) obtaining and including breast cancer risk information in the letters of invitation. A secondary aim is to test the additional effect on participation of a reminder letter. Two randomized studies will be undertaken over three years. The studies will be conducted in a managed healthcare system where risk-based breast cancer screening is already occurring. In the first study a 2x2 factorial design will test the effect of involving the primary care team and the use of reminder letters. Using a four group experimental design, the second study will test the effect on participation of pre-invitation risk assessment and of including breast cancer risk information in the invitations. In both studies, participation will be defined as scheduling an appointment for mammography within six months of receiving the invitation. The long-term objective is to apply the results of this study to population-based screening programs to promote the use of mammography in settings such as managed healthcare systems. community physician practices and regional mammography screening facilities.